As Ebola outbreak rages, vaccine is 97.5% effective, protecting over 90K people

Enlarge / A nurse working
with the World Health Organization (WHO) shows a bottle containing
Ebola vaccine at the town hall of Mbandaka on May 21, 2018 during
the launch of the Ebola vaccination campaign. (credit:
GettyJunior D. Kannah)

An experimental vaccine against the Ebola virus is 97.5 percent
effective at preventing the disease, protecting well over 90,000
people in the massive, ongoing outbreak in the Democratic Republic
of the Congo, according to preliminary data.

The outbreak has flared since last August, involving 1,264
cases (1,198 confirmed; 66 probable) and 814 deaths (748 confirmed,
66 probable), making it the second-largest Ebola outbreak recorded.
So far the outbreak has stayed within the DRC’s North Kivu and
Ituri provinces, which sit on the eastern side of the country,
bordering South Sudan, Uganda, and Rwanda. But, response efforts
have been severely hampered by community distrust of public health
campaigns. One result has been several attacks by militants on
medical facilities, injuring medical staff and, in one case,
killing a police officer. Some public health experts fear the
outbreak will continue to spread without new strategies and more
aid, possibly across nearby borders.

Still, the outbreak could have been far worse if it had not been
for an experimental vaccine. The
rVSV-ZEBOV-GP Ebola vaccine, made by Merck & Co, contains a
live attenuated virus harmless to humans that researchers
genetically engineered to carry an Ebola glycoprotein. Ebola
usually uses this protein to interact with human cells, but in the
vaccine, it triggers the human immune system to generate powerful
antibodies to attack the virus. Early tests of the vaccine seemed
to confirm this, suggesting it is safe and effective. And a World
Health Organization
Strategic Advisory Group of Experts (SAGE) has
given responders the greenlight to use the vaccine during
outbreaks, based on an Expanded Access/Compassionate Use
protocol.